ACCS India

11. Solving Bounded-Diameter Minimum Spanning Tree Problem Using Improved Heuristics
Authors:	Rajiv Saxena and Alok Singh
Abstract:	The bounded-diameter minimum spanning tree (BDMST) problem is to find a minimum spanning tree of a given connected, undirected, edge-weighted graph G in which no path between any two vertices contains more than k edges. The problem is known to be NP-Hard for 4k < n1, where n is the number of vertices in G. Therefore, we look for heuristics to find good approximate solutions. This work is an improvement over two existing greedy heuristics - Improved Randomized Greedy Heuristics (RGH-I) and Improved Centre Based Tree Construction (CBTC-I). Both themselves are improved versions of heuristics RGH and CBTC. The improvement is such that given a bounded-diameter minimum spanning tree T as constructed by RGH or CBTC, the heuristic tries to improve the cost of T further by disconnecting a sub-tree of height h rooted at vertex v in T and attaching it to a vertex where the cost of attaching is minimum without violating the diameter constraint. On 25 Euclidean instances and 20 non-euclidean instances upto 1000 vertices our approach shows substantial improvement over solutions found by RGH-I and CBTC-I.
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12. Ad-hoc Cooperative Computation in Wireless Networks using Ant like Agents
Authors:	Santosh Kulkarni & Prathima Agrawal
Abstract:	Mobile applications continue to soar in popularity as they provide its users the convenience of accessing services from anywhere, at anytime. The underlying computing devices for such applications however, are often limited in their battery and processing powers, primarily due to size and weight restrictions. Running complex applications on such resource-limited devices has always been a challenge. In the work presented here, we address this challenge by proposing a cooperative paradigm for ad-hoc computation in wireless networks. In this model, a set of heterogeneous computing devices cooperate to dynamically form a distributed computation system. Whenever a resource-limited computing device in such a system has resource-consuming application to be run, it uses the resources of other devices to overcome its own limitations. The proposed paradigm is based on the concept of execution migration and relies on migratory execution units called Ant Agents to seek spare resources available in the network. Simulation results for the proposed model demonstrate that cooperative ad-hoc computation is indeed beneficial for resource constrained wireless devices
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13. Optimal Network Partitioning for Distributed Computing Using Discrete Optimization
Authors:	G. Angeline Ezhilarasi & Dr. K. S. Swarup
Abstract:	This paper presents an evolutionary based discrete optimization (DO) technique for optimal network partitioning (NP) of a power system network. The algorithm divides the network model into a number of sub networks optimally in order to balance distributed computing and parallel processing of power system computation and to reduce the communication overhead. The partitioning method is illustrated on IEEE Standard 14 Bus, 30 Bus and 118 Bus Test Systems and compared with the other existing methods. The performance of the algorithm is studied using the test systems with different configurations.
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14. An Efficient Algorithm to Reconstruct a Minimum Spanning Tree in an Asynchronous Distributed System
Authors:	Suman Kundu & Dr. Uttam Kr. Roy
Abstract:	In a highly dynamic asynchronous distributed network, node failure (or recovery) and link failure (or recovery) triggers topological changes. In many cases, reconstructing the minimum spanning tree, after each such topological change, is very much required. In this paper, we have described a distributed algorithm based on message passing to reconstruct the minimum spanning tree after a link failure. The algorithm assumes that no further topological changes occur during the execution of the algorithm. The proposed algorithm requires significantly fewer numbers of messages to reconstruct the spanning tree in comparison to other existing algorithms.
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15. Energy Efficient Cluster Formation using Minimum Separation Distance and Relay CH's in Wireless Sensor Networks
Authors:	V.V.S Suresh Kalepu and Raja Datta
Abstract:	In this work we proposed a scheme to select the relay nodes for forwarding network data when a minimum separation distance (MSD) is maintained between cluster heads in a cluster based sensor network. This prolongs network lifetime by spreading the cluster heads, thus lowering the average communication energy consumption by optimizing the next node for delivery of data. The work also includes the study of the above protocol by varying the network area. We also proposed another cluster-based routing protocol for large network areas, this improves the MSD routing protocol by introducing minimum spanning trees (MST) instead of direct communications to connect nodes in clusters. We have done extensive simulations to show that the proposed method outperforms the existing techniques.
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16. A Broadcast Authentication Protocol for Multi-Hop Wireless Sensor Networks
Authors:	R. C. Hansdah, Neeraj Kumar and Amulya Ratna Swain
Abstract:	A base station in wireless sensor network (WSN) needs to frequently broadcast messages to sensor nodes, since broadcast communication is used in many applications such as networks query, time synchronization, multi-hop routing, etc. One of the main problems of broadcast communication in WSNs is source authentication. Source authentication means that the receivers of broadcast data have to verify that the received data really originated from the claimed source and is not modified on the way. This problem is complicated due to untrusted receivers and unreliable communication environment where the sender does not retransmit the lost packets. In this paper, we propose a novel scheme for authenticating messages from each node of the WSN at the base station using Diffie- Hellman key. Most existing schemes for broadcast authentication using hash key chain are limited to single hop WSNs only. Using the above technique for source node authentication, we extend the broadcast authentication scheme using hash key chain to multi-hop wireless sensor networks. The number of transmissions of packets is also reduced using some selective paths during the broadcast and as a result, the storage and communication overhead is also reduced. The analysis and experiments show that our protocol is efficient and practical, and achieves better performance than the previous approaches.
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17. Energy-efficient Scheduling of Grid Computing Clusters
Authors:	Tapio Niemi, Jukka Kommeri & Ari-Pekka Hameri
Abstract:	Energy-efficiency is an increasingly important component in computation costs in scientific computing. We have studied different scheduling settings with different hardware for high-throughput computing trying to minimize the electricity usage of computing jobs. Instead of common practice of one task per CPU core scheduling in grid clusters, we have tested variations of different scheduling methods based on idea to fully load computing nodes. Our test showed running multiple tasks simultaneously can decrease energy usage per computing task over 40% and improve throughput of the computing node up to 100% when running a high-energy physics (HEP) analysis application. The trade-off is that processing times of individual tasks are longer but in cases, such as HEP computing, in which the tasks are not time critical, only the total throughput is important.
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18. Towards Geometrical Password for Mobile Phones
Authors:	Mozaffar Afaque, M Sarosh Umar, Najaf Zaidi & Mohammed A Qadeer
Abstract:	Mobile cell phones have brought a revolution in the modern world. They have become profound instruments in bringing social as well as financial transformation. Mobile phones today not only hold the key to communication problems but can also be a suitable medium to facilitate commercial and financial transaction. There is an urgent need to establish ways to authenticate people over cell phone. The current method for authentication uses alphanumeric username and password. The textual password scheme is convenient but has its own drawbacks. Alphanumeric passwords are most of the times easy to guess, offer limited possibilities and are easily forgotten. With financial transactions at stake, the need of the hour is a collection of robust schemes for authentication. Graphical passwords are one of such schemes which offer a plethora of options and combinations. We are proposing a scheme which is simple for the user and robust at the same time. Graphical password by drawing geometries will provide a larger password space; at the same time will allow the user to use its photographic memory, making it easy to remember. The proposed scheme is suitable for all touch sensitive mobile phones.
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19. Improving Performance of Speaker Identification System Using Complementary Information Fusion
Authors:	Md. Sahidullah, Sandipan Chakroborty and Goutam Saha
Abstract:	Feature extraction plays an important role as a front-end processing block in speaker identification (SI) process. Most of the SI systems utilize like Mel-Frequency Cepstral Coefficients (MFCC), Perceptual Linear Prediction (PLP), Linear Predictive Cepstral Coefficients (LPCC), as a feature for representing speech signal. Their derivations are based on short term processing of speech signal and they try to capture the vocal tract information ignoring the contribution from the vocal cord. Vocal cord cues are equally important in SI context, as the information like pitch frequency, phase in the residual signal, etc could convey important speaker specific attributes and are complementary to the information contained in spectral feature sets. In this paper we propose a novel feature set extracted from the residual signal of LP modeling. Higher-order statistical moments are used here to find the nonlinear relationship in residual signal. To get the advantages of complementarily vocal cord based decision score is fused with the vocal tract based score. The experimental results on two public databases show that fused mode system outperforms single spectral features.
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20. Right Brain Testing: Applying Gestalt psychology in Software Testing
Authors:	Narayanan Palani
Abstract:	Applying Gestalt psychology in Software Testing can explore innovative paths and new techniques in web testing methodologies. It can address the critical testing processes like test blindness testing, condition testing in complex conditions and web security testing.
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